Videoconferencing uses telecommunications of audio and video to bring people at different sites together for a meeting. This can be as simple as a conversation between two people in private offices (point-to-point) or involve several sites (multipoint) with more than one person in a number of rooms at different sites. Besides the audio and visual transmission of people, videoconferencing can be used to share documents, computer-displayed information, and whiteboards.
In video conferencing applications, many users may share the same channel. Due to channel sharing and limited bandwidth availability, video compression is performed using state of the art video encoding algorithms. To accommodate as many users as possible, an acquired video is typically highly compressed. Due to the compression, a decoded video tends to introduce visually annoying artifacts such as blurring, ringing, and blockiness. For example, the Human Visual System (HVS) exhibits a temporal lowpass filter behavior when exposed to content with motion and sharpness is perceived mostly around edges. Thus, metrics designed for specific artifacts may be employed to determine overall quality of the video objectively.